A base station for compensating for frequency offsets is described. The base station includes a processor and instructions stored in memory. The base station computes a time domain impulse response estimate and applies frequency offset compensation to the time domain impulse response estimate to obtain a time domain offset-compensated impulse response estimate. A frequency domain offset-compensated impulse response estimate is computed. The frequency domain offset-compensated impulse response estimate is used to compute beamforming weights. The base station transmits data using the beamforming weights.
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1. A base station for compensating for frequency offsets, comprising: a processor; memory in electronic communication with the processor; instructions stored in the memory, the instructions being executable to: compute a time domain impulse response estimate; apply frequency offset compensation to the time domain impulse response estimate to obtain a time domain offset-compensated impulse response estimate; compute a frequency domain offset-compensated impulse response estimate; compute beamforming weights using the frequency domain offset-compensated impulse response estimate; form at least one beam using the beamforming weights; and transmit data using the at least one beam.
A base station compensates for frequency offsets by: 1) calculating a time-domain impulse response estimate representing the channel; 2) applying frequency offset compensation to this estimate, correcting for frequency errors and resulting in an offset-compensated time-domain impulse response estimate; 3) converting this corrected time-domain estimate to the frequency domain to obtain a frequency-domain offset-compensated impulse response estimate; 4) using this frequency-domain estimate to calculate beamforming weights; 5) forming one or more beams using these weights; and 6) transmitting data using these beams.
2. The base station of claim 1 , wherein the beamforming weights are used for Spatial Division Multiple Access (SDMA).
The base station from the previous description computes beamforming weights and forms beams used for Spatial Division Multiple Access (SDMA), enabling multiple users to share the same frequency channel simultaneously by spatially separating their signals, therefore increasing the overall system capacity and spectral efficiency.
3. The base station of claim 1 , wherein the base station is an access point.
The base station from the first description is specifically implemented as an access point, providing wireless network access to devices within its range, and performs frequency offset compensation to ensure reliable communication despite frequency drifts or Doppler effects between the access point and connected devices.
4. The base station of claim 1 , further comprising one or more antennas.
The base station from the first description also includes one or more antennas, which are used for transmitting and receiving wireless signals, including the data transmitted using the beams formed with frequency offset compensation.
5. The base station of claim 1 , wherein the instructions are further executable to discover one or more wireless communication devices.
The base station from the first description also discovers one or more wireless communication devices in its vicinity, enabling it to establish connections and communicate with these devices after compensating for frequency offsets.
6. The base station of claim 1 , wherein the data is transmitted to one or more access terminals.
The base station from the first description transmits data to one or more access terminals (e.g., smartphones, laptops), providing wireless connectivity to these devices after applying frequency offset compensation to maintain reliable communication.
7. The base station of claim 1 , wherein the instructions are further executable to receive one or more channel samples with one or more frequency offsets.
The base station from the first description receives one or more channel samples that contain frequency offsets, which the base station then compensates for using the described methods to improve communication accuracy and reliability.
8. The base station of claim 1 , wherein computing a time domain impulse response estimate comprises multiplying the inverse of the Hermitian of a Fast Fourier Transform (FFT) matrix multiplied by the FFT matrix plus a constant multiplied by an identity matrix with the Hermitian of the FFT matrix and received channel samples.
The base station from the first description calculates the time domain impulse response estimate by performing the following calculation: (Inverse(Hermitian(FFT matrix) * FFT matrix + constant * Identity matrix) * Hermitian(FFT matrix) * received channel samples). This process effectively estimates the characteristics of the communication channel in the time domain.
9. The base station of claim 1 , wherein applying frequency offset compensation to the time domain impulse response estimate comprises multiplying the time domain impulse response estimate by an exponential function including a frequency offset.
The base station from the first description applies frequency offset compensation to the time domain impulse response estimate by multiplying the estimate by an exponential function. This exponential function includes a frequency offset parameter, which is used to correct for the frequency difference between the transmitter and receiver.
10. The base station of claim 1 , wherein computing a frequency domain offset-compensated impulse response estimate comprises multiplying the time domain offset-compensated impulse response estimate with a Fast Fourier Transform (FFT) matrix.
The base station from the first description computes a frequency domain offset-compensated impulse response estimate by multiplying the time domain offset-compensated impulse response estimate with a Fast Fourier Transform (FFT) matrix, converting the signal from the time domain to the frequency domain.
11. The base station of claim 1 , wherein computing the time domain impulse response estimate comprises multiplying the inverse of the Hermitian of a Fast Fourier Transform (FFT) matrix multiplied by the FFT matrix plus a constant multiplied by an identity matrix with an Inverse Fast Fourier Transform (IFFT) matrix and received channel samples.
The base station from the first description calculates the time domain impulse response estimate by performing the following calculation: (Inverse(Hermitian(FFT matrix) * FFT matrix + constant * Identity matrix) * Inverse Fast Fourier Transform (IFFT) matrix * received channel samples). This provides an alternative way to estimate channel characteristics in the time domain.
12. The base station of claim 1 , wherein computing a time domain impulse response estimate comprises taking an Inverse Fast Fourier Transform (IFFT) of received channel samples multiplied by a windowing function.
The base station from the first description calculates a time domain impulse response estimate by taking an Inverse Fast Fourier Transform (IFFT) of the received channel samples after multiplying them by a windowing function. The windowing function helps to reduce noise and improve the accuracy of the impulse response estimate.
13. The base station of claim 12 , wherein applying frequency offset compensation to the time domain impulse response estimate comprises multiplying the time domain impulse response estimate by an exponential function including a frequency offset and sample shift to obtain a sample-shifted time domain impulse response.
The base station from the description which uses an IFFT of windowed channel samples to generate a time domain estimate applies frequency offset compensation to the time domain impulse response estimate by multiplying the estimate by an exponential function. This exponential function includes both a frequency offset and a sample shift, resulting in a sample-shifted time domain impulse response.
14. The base station of claim 13 , wherein computing the frequency domain offset-compensated impulse response estimate comprises: computing a sample-shifted frequency domain impulse response estimate by taking the Fast Fourier Transform (FFT) of the sample-shifted time domain impulse response; computing a sample-shifted frequency domain window by taking the FFT of the IFFT of the windowing function multiplied by the exponential function including a frequency offset and sample shift; and computing a frequency domain offset-compensated impulse response estimate for windowing by dividing the sample-shifted frequency domain impulse response by the sample-shifted frequency domain window.
The base station from the description that includes an IFFT of windowed channel samples applies frequency offset compensation as follows: 1) Calculate a sample-shifted frequency domain impulse response estimate by taking the FFT of the sample-shifted time domain impulse response; 2) Calculate a sample-shifted frequency domain window by taking the FFT of the IFFT of the windowing function multiplied by an exponential function (frequency offset and sample shift); 3) Compute a frequency domain offset-compensated impulse response estimate by dividing the sample-shifted frequency domain impulse response by the sample-shifted frequency domain window.
15. The base station of claim 13 , wherein computing the frequency domain offset-compensated impulse response estimate comprises: computing a sample-shifted frequency domain impulse response estimate by taking the Fast Fourier Transform (FFT) of the sample-shifted time domain impulse response; computing a sample-shifted frequency domain window by taking the FFT of the IFFT of the windowing function multiplied by the exponential function including a frequency offset and sample shift; and computing a frequency domain offset-compensated impulse response estimate for windowing by dividing the sample-shifted frequency domain impulse response by the magnitude of the sample-shifted frequency domain window.
The base station from the description that uses an IFFT of windowed channel samples applies frequency offset compensation as follows: 1) Calculate a sample-shifted frequency domain impulse response estimate by taking the FFT of the sample-shifted time domain impulse response; 2) Calculate a sample-shifted frequency domain window by taking the FFT of the IFFT of the windowing function multiplied by an exponential function (frequency offset and sample shift); 3) Compute a frequency domain offset-compensated impulse response estimate by dividing the sample-shifted frequency domain impulse response by the magnitude of the sample-shifted frequency domain window.
16. A method for compensating for frequency offsets on a base station, comprising: computing, on a base station, a time domain impulse response estimate; applying, on the base station, frequency offset compensation to the time domain impulse response estimate to obtain a time domain offset-compensated impulse response estimate; computing, on the base station, a frequency domain offset-compensated impulse response estimate; computing, on the base station, beamforming weights using the frequency domain offset-compensated impulse response estimate; forming, on the base station, at least one beam using the beamforming weights; and transmitting data using the at least one beam from the base station.
A method for compensating for frequency offsets on a base station involves: 1) computing a time domain impulse response estimate; 2) applying frequency offset compensation to the time domain impulse response estimate to obtain a time domain offset-compensated impulse response estimate; 3) computing a frequency domain offset-compensated impulse response estimate; 4) computing beamforming weights using the frequency domain offset-compensated impulse response estimate; 5) forming at least one beam using the beamforming weights; and 6) transmitting data using the at least one beam.
17. The method of claim 16 , wherein the beamforming weights are used for Spatial Division Multiple Access (SDMA).
The method described in the previous description uses beamforming weights for Spatial Division Multiple Access (SDMA), enabling simultaneous communication with multiple users on the same frequency channel by spatially separating their signals using beamforming.
18. The method of claim 16 , wherein the base station is an access point.
The method described in the previous description is performed on a base station that is an access point, providing wireless network access and compensating for frequency offsets to ensure reliable communication.
19. The method of claim 16 , wherein the base station uses one or more antennas.
The method described in the previous description is performed on a base station that uses one or more antennas for transmitting and receiving wireless signals, including the data transmitted using the beams formed with frequency offset compensation.
20. The method of claim 16 , wherein the instructions are further executable to discover one or more wireless communication devices.
The method described in the previous description also involves discovering one or more wireless communication devices, allowing the base station to establish connections and communicate with these devices after compensating for frequency offsets.
21. The method of claim 16 , wherein the data is transmitted to one or more access terminals.
The method described in the previous description involves transmitting data to one or more access terminals (e.g., smartphones, laptops), providing wireless connectivity to these devices after applying frequency offset compensation.
22. The method of claim 16 , further comprising, receiving one or more channel samples with one or more frequency offsets.
The method described in the previous description also includes receiving one or more channel samples with one or more frequency offsets, which are then compensated for to improve communication accuracy and reliability.
23. The method of claim 16 , wherein computing a time domain impulse response estimate comprises multiplying the inverse of the Hermitian of a Fast Fourier Transform (FFT) matrix multiplied by the FFT matrix plus a constant multiplied by an identity matrix with the Hermitian of the FFT matrix and received channel samples.
In the method described in the first method claim, computing a time domain impulse response estimate involves multiplying the inverse of (Hermitian(FFT matrix) * FFT matrix + constant * Identity matrix) with (Hermitian(FFT matrix) * received channel samples). This calculation provides an estimate of the communication channel's characteristics in the time domain.
24. The method of claim 16 , wherein applying frequency offset compensation to the time domain impulse response estimate comprises multiplying the time domain impulse response estimate by an exponential function including a frequency offset.
In the method described in the first method claim, applying frequency offset compensation involves multiplying the time domain impulse response estimate by an exponential function including a frequency offset, effectively correcting for frequency differences between the transmitter and receiver.
25. The method of claim 16 , wherein computing a frequency domain offset-compensated impulse response estimate comprises multiplying the time domain offset-compensated impulse response estimate with a Fast Fourier Transform (FFT) matrix.
In the method described in the first method claim, computing a frequency domain offset-compensated impulse response estimate involves multiplying the time domain offset-compensated impulse response estimate with a Fast Fourier Transform (FFT) matrix, converting the signal from the time domain to the frequency domain.
26. The method of claim 16 , wherein computing the time domain impulse response estimate comprises multiplying the inverse of the Hermitian of a Fast Fourier Transform (FFT) matrix multiplied by the FFT matrix plus a constant multiplied by an identity matrix with an Inverse Fast Fourier Transform (IFFT) matrix and received channel samples.
In the method described in the first method claim, computing the time domain impulse response estimate involves multiplying the inverse of (Hermitian(FFT matrix) * FFT matrix + constant * Identity matrix) with (an Inverse Fast Fourier Transform (IFFT) matrix * received channel samples). This is an alternative way to calculate the channel impulse response in the time domain.
27. The method of claim 16 , wherein computing a time domain impulse response estimate comprises taking an Inverse Fast Fourier Transform (IFFT) of received channel samples multiplied by a windowing function.
In the method described in the first method claim, computing a time domain impulse response estimate comprises taking an Inverse Fast Fourier Transform (IFFT) of received channel samples multiplied by a windowing function, which helps to reduce noise and improve the accuracy of the impulse response estimate.
28. The method of claim 27 , wherein applying frequency offset compensation to the time domain impulse response estimate comprises multiplying the time domain impulse response estimate by an exponential function including a frequency offset and sample shift to obtain a sample-shifted time domain impulse response.
In the method, which uses an IFFT of windowed channel samples to generate a time domain estimate, applying frequency offset compensation involves multiplying the time domain impulse response estimate by an exponential function including a frequency offset and sample shift, resulting in a sample-shifted time domain impulse response.
29. The method of claim 28 , wherein computing the frequency domain offset-compensated impulse response estimate comprises: computing a sample-shifted frequency domain impulse response estimate by taking the Fast Fourier Transform (FFT) of the sample-shifted time domain impulse response; computing a sample-shifted frequency domain window by taking the FFT of the IFFT of the windowing function multiplied by the exponential function including a frequency offset and sample shift; and computing a frequency domain offset-compensated impulse response estimate for windowing by dividing the sample-shifted frequency domain impulse response by the sample-shifted frequency domain window.
The method from the previous description, which involves IFFT of windowed channel samples applies frequency offset compensation as follows: 1) Calculating a sample-shifted frequency domain impulse response estimate by taking the FFT of the sample-shifted time domain impulse response; 2) Calculating a sample-shifted frequency domain window by taking the FFT of the IFFT of the windowing function multiplied by an exponential function (frequency offset and sample shift); 3) Computing a frequency domain offset-compensated impulse response estimate by dividing the sample-shifted frequency domain impulse response by the sample-shifted frequency domain window.
30. The method of claim 28 , wherein computing the frequency domain offset-compensated impulse response estimate comprises: computing a sample-shifted frequency domain impulse response estimate by taking the Fast Fourier Transform (FFT) of the sample-shifted time domain impulse response; computing a sample-shifted frequency domain window by taking the FFT of the IFFT of the windowing function multiplied by the exponential function including a frequency offset and sample shift; and computing a frequency domain offset-compensated impulse response estimate for windowing by dividing the sample-shifted frequency domain impulse response by the magnitude of the sample-shifted frequency domain window.
The method from the description including IFFT of windowed channel samples applies frequency offset compensation as follows: 1) Calculating a sample-shifted frequency domain impulse response estimate by taking the FFT of the sample-shifted time domain impulse response; 2) Calculating a sample-shifted frequency domain window by taking the FFT of the IFFT of the windowing function multiplied by an exponential function (frequency offset and sample shift); 3) Computing a frequency domain offset-compensated impulse response estimate by dividing the sample-shifted frequency domain impulse response by the magnitude of the sample-shifted frequency domain window.
31. A computer-program product for compensating for frequency offsets on a base station, the computer-program product comprising a non-transitory computer-readable medium having instructions thereon, the instructions comprising: code for computing a time domain impulse response estimate; code for applying frequency offset compensation to the time domain impulse response estimate to obtain a time domain offset-compensated impulse response estimate; code for computing a frequency domain offset-compensated impulse response estimate; code for computing beamforming weights using the frequency domain offset-compensated impulse response estimate; code for forming at least one beam using the beamforming weights; and code for transmitting data using the at least one beam.
A computer program product stored on a non-transitory computer-readable medium compensates for frequency offsets on a base station by including: 1) code for computing a time domain impulse response estimate; 2) code for applying frequency offset compensation to the time domain impulse response estimate to obtain a time domain offset-compensated impulse response estimate; 3) code for computing a frequency domain offset-compensated impulse response estimate; 4) code for computing beamforming weights using the frequency domain offset-compensated impulse response estimate; 5) code for forming at least one beam using the beamforming weights; and 6) code for transmitting data using the at least one beam.
32. An apparatus for compensating for frequency offsets, comprising: means for computing a time domain impulse response estimate; means for applying frequency offset compensation to the time domain impulse response estimate to obtain a time domain offset-compensated impulse response estimate; means for computing a frequency domain offset-compensated impulse response estimate; means for computing beamforming weights using the frequency domain offset-compensated impulse response estimate; means for forming at least one beam using the beamforming weights; and means for transmitting data using the at least one beam.
An apparatus for compensating for frequency offsets includes: 1) a means for computing a time domain impulse response estimate; 2) a means for applying frequency offset compensation to the time domain impulse response estimate to obtain a time domain offset-compensated impulse response estimate; 3) a means for computing a frequency domain offset-compensated impulse response estimate; 4) a means for computing beamforming weights using the frequency domain offset-compensated impulse response estimate; 5) a means for forming at least one beam using the beamforming weights; and 6) a means for transmitting data using the at least one beam.
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July 28, 2010
July 30, 2013
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